Air heater



Sept..30, 1930. w. H. OWEN 1 ,777,148

AIR HEATER Filed March 30, 1927 Patented Sept. 30, 1930 UNHTED STATESWILLIAM HENRY OWEN, OF WIIEBLEDON, ENGLAND AIR HEATER Application filedMarch 30, 1927, Serial No. 179,668, and in Great Britain April 8, 1928.

This invention relates to that class of air heaters in which the heatingelements or cells, in any convenient number are assembled together toform several groups or bundles which are contained in a casing providedwith doors for access etc. The side of the casing has openings or portsfor the entrance and exit of the air to and from the cells, which havesuitable openings in their back edges for this purpose. The air is ledto the ports by an exterior longitudinal duct.

For the purpose of preventing the escape of air into the gas spaces, orfrom the cold air inlets to the heated air outlets, it is necessary tomake an air tight joint between the back face of the bundles and thesurface of the casing. It is an object of the present invention toprovide a simple and an effective method of making this joint, whichwhilst readily detachable at the same time gives a rigid constructionfor holding the cells to gether.

In order to carry the invention into effect, I propose to attach, bywelding or otherwise, to the back face of the bundles, a channel or anangle iron frame situated on the periphery of the bundles, and exteriorto the air orifices. In the space left between the webs of the channeliron, a strip of rope of asbestos, or other elastic and heat resistingmaterial, is fixed projecting above the webs so that when the bundle isforced against the side of the casing, by screws, crossbars or othersuitable means, the asbestos is squeezed between the two parts and thejoint is made. This prevents escape of the heating medium or hot wastegas which flows through the casing, and also prevents air from theair-inlets leaking into such casing. Alternatively, instead of asbestosor the like material, a quantity of heat resisting cement may be putinto the space of the channel iron.

An alternative construction is to fix to the back face of the bundles aplate pierced with slots having the desired pitch of the cells. The openedges of the air cells would be placed in the slots, and the edges ofthe cells would then be welded or otherwise secured to the sides of theslots thus forming a secure and an air tight connection binding thewhole rigidly together. An angle or channel iron frame is fixed to theface of the plate exterior to the air orifices, by riveting, welding orother convenient means. In some cases these frames may be dispensed withand the ashestos be fixed directly onto the face of the plate, or heatresisting cement only may be used.

It is obvious that the arrangement may be reversed and that the channelor angle iron frames may be fixed onto the casing instead of to thebundles or to the plate fixed to the latter. In all cases a cross joint,between the orifices for the air, is provided in order to preventleakage of cold air to the hot air exit.

In this way the bundle forms a self-com tained unit in which alternatecells form through passages for the heating medium or hot waste gas,whilst the intervening cells with openings only at one side serve asheaters for the medium to be heated. This self contained unit is easilydetachable and replaceable.

In order to give a more intense pressure on F the asbestos packing anangle or channel iron frame may be fixed onto the bundle or to thecasing so that the asbestos in the opposite channel or angle iron framewould be indented by the narrow projecting web or, if cement be used, itwould be squeezed out as the web entered and thus make a sound joint allround the edges. 7

In order that the invention may be clearly understood and readilycarried into efiect reference will now be had by way of example to theaccompanying diagrammatic drawings in which:

Fig. 1 is a side view of one arrangement according to the invention.

Fig. 2 is an elevation of the bundle or heattlgansfer unit lookingtowards the left (Fig. 1

Fig. 3 is a horizontal section thereof taken on the line 33 of Fig. 1.

Fig. 4 is a side view partly in section of a modification hereinafterreferred to.

Fig. 5 is a front view, and

Fig. 6 is a horizontal section thereof.

Figs. 7 and 8 illustrate in side View, further modifications.

til)

Referring more particularly to Figs. 1 to a indicates a bundle, group orbox of cells, which is provided with an angle-iron frame 6.

c c are tie-bolts which pass through the frame and have tightening nutsd at each end. These belts pass through distance pieces, rings orwashers e in the mouths of the air spaces between the edges of the thinplates (1 of the heater, and through closing bars f in the waste gasspaces, the whole being thus clamped securely together to form apermanent bundle or group of cells.

The edges of the plates of each heating cell are bent together so thatthey meet central'iy, where they are seamed or Welded, so as to closethree sides of the cell. The fourth side, or mouth, is of course open.To keep the cells together and in proper relative position, the verticalclosed edges (that is, those on the right in Fig. 1) are spot welded toa bar u running across the middle of the bundle or unit, as indicatedalso in Fig. 2.

The air-heating cells are thus formed by the alternate spacescorresponding to the distance rings e, whilst the intervening spaces orcells (corresponding to the closing bars 7') serve as direct-throughpassages for the upflow of the waste-gases, being open at the top andbottom. Any other convenient way of keeping the cells in position, andholding them together, may be employed however, if desired, instead ofthe centre cross-bar (F i 2).

The angle-iron-frame may be welded to the cells all around the edges,and the edges of the cells may be welded to the vertical spacing bars inthe gas spaces. The bundles are arranged in an outer casing a providedwith one or more doors s is the duct for supplying cold air, whilst onis the duct for taking away the heated air, suitable openings n in thecasing being provided for conducting the air to and from the cells.

The hot waste gases and smoke pass strai ht up through the casing 8 andthe bundles Iiy means of the alternate spaces, VlZ, those which have thebars f in their lefthand edges (Fig. 3).

Asbestos or other suitable packing p placed between the faces of theangle-iron frame b and the inside of the casing of the ducts to preventleakage of air, such angle-iron framing being forced onto the asbestosby bolts g. The frame may be of channel section, as at y (Figs 4 to 6)and the asbestos or the like packed into it so as to project normally asshown. The frame may however be set back as at b (Fig. 7) slightly ontothe casing, and strip 12 be provided at the middle. An alternativemethod is to provide a crossbar Q) fixed in the outer casing s withscrews 1) to force the bundle on to the face of the casing, a bar (u)welded to the edges of the cells being provided to distribute thepressure and to bind the cells together.

Another method of forming the joint is to fix the mouths of the cells,or rather the pairs of plates a at their edges, into a plate pro videdwith slots w for the entrance and exit of air.

The edges of the cells may be welded to the strips or bars m leftbetween the slots w.

The channel-iron frame y is fixed to the slotted plate in any convenientmanner, the packing p being held in the groove of the channel iron.

In some cases, when the cells a and plates (1 are of considerablelength, the ducts and m may be placed near the top and bottom (Fig. 8)otherwise made air tight the joints, as in the manner illustrated in thepreceding figures. Moreover if desired, or on account of considerationsof space, the door a may be placed at the end of the casing, so that theboxes or bundles a may be inserted or drawn out sidewise.

I claim 1. In an air heater, the combination of a casing serving as aflue for waste gases, inlet and outlet air-ducts arranged at one side ofsaid casing and opening thereto, a detachable bundle of plates forming asingle unit and comprising alternate cells to receive respectively thewaste gases and the air to be heated, packing arrangements at one andthe same side of said bundle to form joints around the openings of thecasing and air-ducts, means for securing said bundle in place and forcompressing said packing, and a door arrangement opposite the bundle forpermitting its ready insertion into and removal from the casing,substantially as described.

2. In an air-heater, the combination of a casing through which theheating medium passes, ducts at one side thereof for the admission andwithdrawal of the air to be heated, a bundle of plates forming a singleunit arranged inside said casing and communicating with said ducts,alternate cells in said bundle forming direct through passages for theheating medium, intervening cells open on one side only to both theairducts, an angle-iron frame for holding packing around the jointbetween the edge of the bundle and the aforesaid casing, and means forsimultaneously compressing such packing and fixing said bundle inposition, substantially as described.

3. In an air-heater, the combination of a casing for the passage ofwaste gases, inlet and outlet air ducts at one side of said casing, abundle of plates forming a single detachable unit and comprising cellsof which alternate ones serve for the direct flow of the waste gaseswhilst the intervening ones serve for the air to be heated, suchintervening cells having inlet and outlet openings at one sidecommunicating with the aforesaid inlet and outlet ducts, and anangle-iron frame provided with packing for the joints around the edge ofthe detachable bundle and between the said bundles and the air ducts,substantially as described.

4:. A heat-transfer unit comprising a plurality of similar cellsarranged side by side at spaced intervals, the cells being closed exceptas to one edge, the open edges of the cells being similarly directed andprovided with closing means between them, a transverse strip across theopen edges of the cells intermediate the top and bottom to provide inletand outlet ports to said cells, and jointing frames surrounding all thealigned inlet ports and all the aligned outlet ports, said frames havingjointing flanges lying in a single plane, substantially as describecL 5.A heat-transfer unit comprising alternate parallel cells spaced apartwith lateral openings for the medium to be heated, the spaces betweenthe cells having upper and lower openings for the direct passage throughthem of the heating medium, and

a rigid jointing frame secured to the unit around the openings of theheating cells to strengthen the unit, and to serve for compressingpacking, when the unit is clamped in position for use, substantially asdescribed.

6. A heat-transfer unit consisting of a bundle of parallel plates thealternate spaces between which form heating cells, means for closing theintervening spaces between the 1 months of said cells, and a jointingface surrounding said mouths and adapted to compress packing materialwhen the unit is forced against such packing, substantially asdescribed.

In testimony whereof I afix my signature.

WILLIAM HENRY OWEN.

